1. Field of Invention
This invention is directed to a method and an apparatus to obtain uniform coupling in and out from a nonreciprocal resonator supporting single-mode operation. Switches are inserted with inner and outer feeder networks so that unique phases result exhibiting symmetry. As such, the circuit of a digital phaser gives nominally constant insertion loss over phase selection.
2. Prior Art
The prior art U.S. Pat. No. 6,483,393 B1 by the same author disclosed method and apparatus of obtaining phase shift using non-reciprocal resonator. However, the prior art did not specify, in explicit examples, the necessary feeder networks coupling in and out a nonreciprocal resonator so as to achieve the desired phase shift operation. Although it is possible, by all means, to realize the phaser operation by incorporating transmission lines of an equal electrical length, microwave circuits obtained in this manner are bulky and impractical, resulting in high insertion losses and high costs.